package com.hmdp.service.impl;

import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSON;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisData;
import com.hmdp.utils.SystemConstants;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.geo.GeoSearchArgs;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;

import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.RedisConstants.*;
import static com.hmdp.utils.SystemConstants.DEFAULT_PAGE_SIZE;

/**
 * <p>
 * 服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
@Slf4j
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private CacheClient cacheClient;

    @Override
    public Result queryById(Long id) {
        //缓存穿透
        Shop shop = cacheClient.queryWithPassThrough(CACHE_SHOP_KEY, id,
                Shop.class,
                this::getById,
                CACHE_SHOP_TTL, TimeUnit.MINUTES);
        //缓存击穿
//        Shop shop = queryWithMutex(id);
//        Shop shop = cacheClient.queryWithLogicExpire(CACHE_SHOP_KEY,id,
//                Shop.class,
//                this::getById,
//                CACHE_SHOP_TTL,TimeUnit.MINUTES);
        if (shop == null) {
            return Result.fail("店铺不存在");
        }
        //7 返回
        return Result.ok(shop);
    }

    /**
     * 逻辑过期解决缓存击穿
     * 需要提前将热点数据加载进redis缓存
     */
/*    public Shop queryWithLogicExpire(Long id) {
        //1 从redis中查询缓存
        String shopKey = CACHE_SHOP_KEY + id;
        String shopJson = stringRedisTemplate.opsForValue().get(shopKey);
        //2 判断是否存在
        if (StrUtil.isBlank(shopJson)) {
            //3 不存在，直接返回
            return null;
        }
        //4 存在，需要先把json反序列化为对象
        RedisData redisData = JSONUtil.toBean(shopJson, RedisData.class);
        Shop shop = JSONUtil.toBean((JSONObject) redisData.getData(), Shop.class);
        LocalDateTime expireTime = redisData.getExpireTime();
        //5 判断是否过期
        if (expireTime.isAfter(LocalDateTime.now())) {
            //5.1 未过期，直接返回店铺数据
            return shop;
        }
        //5.2 已过期，需要重建缓存
        //6 缓存重建
        //6.1 获取互斥锁
        String lockKey = LOCK_SHOP_KEY + id;
        boolean isLock = tryLock(lockKey);
        //6.2 判断是否获取锁成功
        if (isLock) {
            //开启独立线程，实现缓存重建
            CACHE_REBUILD_EXECUTOR.submit(()->{
                try {
                    this.saveShop2Redis(id,20L);
                } catch (Exception e) {
                    throw new RuntimeException(e);
                } finally {
                    unlock(lockKey);
                }
            });
        }

        //6.4 当前线程直接返回过期商铺信息
        return shop;
    }*/

    /**
     * 互斥锁解决缓存击穿
     */
    /*public Shop queryWithMutex(Long id) {
        //1 从redis中查询缓存
        String shopKey = CACHE_SHOP_KEY + id;
        String shopJson = stringRedisTemplate.opsForValue().get(shopKey);
        //2 判断是否存在
        if (StrUtil.isNotBlank(shopJson)) {
            //3 存在，直接返回
            return JSONUtil.toBean(shopJson, Shop.class);
        }
        //判断命中的是否是空值
        if (shopJson != null) {
            return null;
        }
        //4 不存在，实现缓存重建

        String lockKey = LOCK_SHOP_KEY + id;
        Shop shop = null;
        try {
            //4.1 获取互斥锁
            boolean isLock = tryLock(lockKey);
            //4.2 判断是否获取锁成功
            if (!isLock) {
                //4.3 失败，则休眠重试
                Thread.sleep(50);
                //递归
                queryWithMutex(id);
            }
            //4.4 获取锁成功，再次查询redis缓存是否存在
            //2 判断是否存在
            shopJson = stringRedisTemplate.opsForValue().get(shopKey);
            if (StrUtil.isNotBlank(shopJson)) {
                //3 存在，直接返回
                return JSONUtil.toBean(shopJson, Shop.class);
            }
            //判断命中的是否是空值
            if (shopJson != null) {
                return null;
            }
            //4.5 redis缓存中没有数据，则查询数据库
            shop = getById(id);
//            Thread.sleep(200);
            //5 若数据不存在
            if (shop == null) {
                //将空值写入redis,解决缓存穿透问题
                stringRedisTemplate.opsForValue().set(shopKey, "", CACHE_NULL_TTL, TimeUnit.MINUTES);
                //返回错误信息
                return null;
            }
            //6 存在，先将数据写入redis,加入过期时间
            stringRedisTemplate.opsForValue().set(shopKey, JSONUtil.toJsonStr(shop), CACHE_SHOP_TTL, TimeUnit.MINUTES);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        } finally {
            //7 释放锁
            unlock(lockKey);
        }
        //8 返回
        return shop;
    }*/

    /**
     * 解决缓存穿透
     *
     * @param
     * @return
     */
/*    public Shop queryWithPassThrough(Long id) {
        //1 从redis中查询缓存
        String shopKey = CACHE_SHOP_KEY + id;
        String shopJson = stringRedisTemplate.opsForValue().get(shopKey);
        //2 判断是否存在
        if (StrUtil.isNotBlank(shopJson)) {
            //3 存在，直接返回
            return JSONUtil.toBean(shopJson, Shop.class);
        }
        //判断命中的是否是空值
        if (shopJson != null) {
            return null;
        }

        //4 不存在，根据id查询数据库
        Shop shop = getById(id);
        //5 若数据不存在
        if (shop == null) {
            //将空值写入redis,解决缓存穿透问题
            stringRedisTemplate.opsForValue().set(shopKey, "", CACHE_NULL_TTL, TimeUnit.MINUTES);
            //返回错误信息
            return null;
        }
        //6 存在，先将数据写入redis,加入过期时间
        stringRedisTemplate.opsForValue().set(shopKey, JSONUtil.toJsonStr(shop), CACHE_SHOP_TTL, TimeUnit.MINUTES);
        //7 返回
        return shop;
    }*/
    @Override
    @Transactional
    public Result update(Shop shop) {
        Long shopId = shop.getId();
        if (shopId == null) {
            return Result.fail("店铺id不能为空");
        }
        String shopKey = CACHE_SHOP_KEY + shopId;
        //1 更新数据库
        updateById(shop);
        //2 删除缓存
        stringRedisTemplate.delete(shopKey);
        return Result.ok();
    }

    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        //判断是否需要按照坐标查询
        if (x == null || y == null) {
            //不需要坐标查询，直接查询数据库
            // 根据类型分页查询
            Page<Shop> page = query()
                    .eq("type_id", typeId)
                    .page(new Page<>(current, DEFAULT_PAGE_SIZE));
            // 返回数据
            return Result.ok(page.getRecords());
        }
        //计算分页参数
        int from = (current - 1) * DEFAULT_PAGE_SIZE;
        int end = current * DEFAULT_PAGE_SIZE;
        //按照距离排序，分页，查询 redis
        String key = SHOP_GEO_KEY + typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo()
                .search(key,
                        GeoReference.fromCoordinate(x, y),
                        new Distance(5000),
                        RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs()
                                .includeDistance().limit(end));
        //根据结果解析 shopId
        if (results == null) {
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();
        log.error("list.size {}", list.size());
        //截取 from ～ end 的部分
        List<Long> ids = new ArrayList<>(list.size());
        Map<String, Distance> distanceMap = new HashMap<>(list.size());
        list.stream().skip(from).forEach(result -> {
            //获取店铺 id
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            //获取店铺距离
            Distance distance = result.getDistance();
            distanceMap.put(shopIdStr, distance);
        });
        //根据 id查询店铺信息
        if (ids == null || ids.size() == 0) {
            return Result.ok(Collections.emptyList());
        }
        String idStr = StrUtil.join(",", ids);
        List<Shop> shopList = query()
                .in("id", ids)
                .last("ORDER BY FIELD(id," + idStr + ")")
                .list();
        for (Shop shop : shopList) {
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }
        return Result.ok(shopList);
    }
/*
    private boolean tryLock(String key) {
        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", 10, TimeUnit.SECONDS);
        return BooleanUtil.isTrue(flag);
    }

    private void unlock(String key) {
        stringRedisTemplate.delete(key);
    }*/

    /**
     * 将店铺数据提前写入redis,并设置逻辑过期
     * @param id
     * @param expireSeconds
     */
/*    public void saveShop2Redis(Long id, Long expireSeconds) throws InterruptedException {
        //1 查询店铺数据
        Shop shop = getById(id);
        Thread.sleep(200);
        //2 封装逻辑过期时间
        RedisData redisData = new RedisData();
        redisData.setData(shop);
        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expireSeconds));
        //3 写入redis
        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id, JSONUtil.toJsonStr(redisData));
    }*/
}
